Even if you have spent hours in the gym burning fat and toning your physique, did you know most of that hard work can become unraveled simply by skipping just a few workouts?

When you exercise on a regular basis, you not only gain physical benefits, but neurological ones as well. Although these gains only take a few weeks to notice, they can disappear just as quickly once the exercise stops. Inigo Mujika, sports physiologist, states that it takes twice as long as an inactive period to get back into shape. For example, if you stop your normal exercise routine for a period of two weeks, it will take up to four weeks to resume your previous level of fitness.

Why do fitness levels drop after two weeks of inactivity?

Even though the body needs time to recover after an intense bout of physical activity, completely skipping workouts for a period as short as two weeks is enough to qualify you as 'out of shape'.

A study published in the Journal of Applied Physiology showed that ceasing exercise for two weeks is enough to greatly reduce insulin sensitivity, lean muscle mass and cardiovascular fitness. During that time, a measure of cardiovascular endurance known as a VO2 max will begin to drop at a rate of half a percent a day.

In a related study, researchers determined that not only can a person's VO2 max drop 7 percent after a 12-day period of inactivity, but enzymes associated with endurance levels can drop by 50 percent. It was also discovered that endurance cyclists experienced a 20 percent drop in VO2 levels following a 4-week period of inactivity. Even trained athletes lost all VO2 gains after being inactive for 4 weeks.

Does inactivity cause muscle loss?

Although cardiovascular gains deplete quickly during periods of inactivity, strength gains do not recede as fast. Newly-made gains appear to stay in place even after a several-month period of inactivity. Researchers studied a group of untrained men who participated in a strength-training program for a period of 15 weeks. IN the middle of the program, the men took a 3-week break, with no decrease in strength levels after the training program resumed.

Skipping exercise can increase the risk of death

Most experts recommend exercising for a minimum of 30 minutes per day, five days per week. Simply doing this is enough to reduce your risk of death from many factors by 19 percent. By increasing the recommended exercise rate to 7 days per week, the initial 19 percent increases to 24.

A related study proved that individuals who led sedentary lifestyles have a much greater risk of death due to heart disease as those who exercise on a daily basis.

Should you ever skip a workout?

No matter what your fitness level, there may be times when it is necessary to take a small break between workouts. If you have a fever, suffering from an illness such as the flu, are injured, or are experiencing fatigue, you may need to take a step back from working out. Consider this time to be a sort of 'recovery' process, but do not get into the habit of consistently missing an exercise session.

No matter what type of exercise you perform, remember that something is always better than nothing. If you become bored with your current workout routine, don't just simply throw in the towel. Take a short while to try other activities until you find one you like. For example, if you love running but are beginning to find it monotonous, try yoga instead. Sometimes this type of switch is just what you need to ignite your passion for fitness again and prevent you from stopping entirely.